The invention is directed to a high spatial and spectral resolution hyperspectral imaging workstation that is capable of capturing hyperspectral imaging in both the ultraviolet (UV) and visible and near-infrared range (“VNIR”) portions of the electromagnetic spectrum. In particular, the hyperspectral imaging workstation according to the invention includes sensors for acquiring separate image data sets in the 200–400 nanometer range (UV) and in the 400–1,000 nanometer (VNIR). The system according to the invention is capable of performing wavelength specific feature extraction and other spectral comparisons on the resulting data sets.
Hyperspectral imaging systems in general are known, and have been used for a diverse range of remote sensing and other analytical techniques, such as is disclosed, for example, in U.S. Pat. No. 5,790,188 and the related U.S. Pat. No. 6,211,906. Hyperspectral imaging has also been used in conjunction with microscopic optical systems, such as disclosed, for example, in U.S. Pat. No. 6,495,818. In such systems, radiation reflected by or emanating from a target or specimen is detected in a large number of narrow contiguous spectral bands, producing a data set which is distributed not only spatially, but spectrally as well. That is, for each pixel within an image of the target, information is recorded in each of the spectral bands, thereby producing a three-dimensional hyperspectral image cube, in which spectral information for each pixel is distributed across a spectral axis perpendicular to the spatial axes.
Previously known hyperspectral imaging workstations, such as the model UV 100E, VNIR 100E, and SWIR 100E provided, for example, by ProVision Technologies of Stennis Space Center, MS, have been capable of capturing hyperspectral image data, for example, within the UV range, from 200 to 400 nanometers, the VNIR range, from 400 to 1,000 nanometers, and the SWIR range from 900 to 2400 nanometers. However, heretofore, no such workstation has been available which produces highly correlated contiguous spectral band data throughout a range from 200 to 1,000 nanometers; that is, including not only the VNIR range, but the UV range as well.
Accordingly, one object of the present invention is to provide a hyperspectral imaging workstation that includes sensors for acquiring separate image data sets in both the ultraviolet and the visible and near-infrared ranges of the electromagnetic spectrum.
Another object of the present invention is to provide a hyperspectral imaging workstation that is capable of providing hyperspectral and imaging data for a large number of contiguous spectral bands throughout a range of from 200 to 1,000 nanometers.
These and other objects and advantages are achieved by the hyperspectral imaging apparatus according to the present invention which includes both UV and VNIR sensors together in a single enclosure. Each sensor captures an image of the target or specimen, resulting in respective UV and VNIR data sets which are then merged into a single hyperspectral data set which includes highly correlated contiguous spectral bands throughout a range of from 200 to 1,000 nanometers, or are provided seperately per end-user software settings.
The system according to the invention permits the detection and analysis of small nuances and information that are otherwise undetectable in systems that use a wide swath filter. Also, the entire range, from 200 to 1,000 nanometers can be used to identify pertinent wavelengths across a wide yet largely defined region of the electromagnetic spectrum for a wide variety of applications that can be programmed as algorithms within the system, or used to develop derivative systems. For example, certain inks that need to be defined when looking at genuine versus counterfeit documents may show regions of interest in both the UV and IR ranges, while others may be found within the visible portion of the electromagnetic spectrum.
Furthermore, the combination of a controlled lighting environment and the ability to use National Institute of Standards and Technology (NIST) traceable diffuse reflectance standards with each scan insures consistent and reproducible results.
The system according to the invention is run by a programmed data processor/software or computer that triggers the lights, hyperspectral cameras and computerized translation stage to acquire and process a fully explorable hyperspectral data cube. The translation stage moves beneath the sensors, allowing the line slit on the optical devices to acquire the entire target. The latter process is performed separately by both cameras, within separate ranges. Thereafter, the resulting data sets are combined in a known manner or provided separately per end-user software settings.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.